A technique through a PPP tunneling (a communication between different communication protocols) dedicated to a wireless communication has been proposed as an encryption communication system between the server and the client via the internet (for example, refer to a Patent Document 1).
This communication system performs a layer-2 encryption mechanism for protecting a path between a terminal equipment and a mobile network and performs a user oriented SIM (IC card) based authentication to access a WLAN (Wireless LAN) for which an IP connectivity is provided.
In this document, an AKA dialogue PPP tunneling between access controllers to access the mobile communication network carrying terminals and the SIM is established. For the same purpose, each of the terminals includes: a PPPoE server (Point-to-Point over Ethernet: registered trade mark) for performing a tunneling of the AKA dialogue from a PPP client installed within each of the terminals and further includes a traffic router and a RADIUS-client. An AC including a RADIUS-client is disposed between the mobile networks in which a RADIUS proxy and SIM based authentication are performed for which an Access Point (AP) within the WLAN is carried out.
[Patent Document 1] a Japanese PCT Application Translation Publication (Tokkouhyo) No. JP2005-524341.